{"ok":true,"entry":{"slug":"ketotifen","kind":"medication","name":"ketotifen","aliases":["Zaditen"],"brands_sg":["Tofen","Ketotifen Syrup","Asumalife"],"class":"antihistamine / mast-cell stabiliser","tags":["allergy"],"use_for":"sg label: allergic rhinitis and chronic urticaria","use_after":"sg pharmacy-supply cap: 2 mg a day, up to 10 days","use_duration":null,"take_with":null,"pros":["pharmacist supply allowed up to 2 mg a day, 10 days","cochrane: better asthma and wheeze control in children","syrup form is registered in sg, from 3 years up"],"cons":["hsa: all 3 sg ketotifen products are prescription-only","cochrane: sedation in 21% vs 12% on placebo","cochrane: weight gain in 27% vs 17% on placebo"],"dose_note":"the singapore label maximum sits in the exemption block of the moh national drug formulary page for TOFEN TABLET 1 MG [SIN09651P], which reads \"As an oral solid preparation not exceeding 2mg — Indications: Symptomatic treatment of allergic rhinitis and chronic urticaria — Maximum daily dose: 2mg — Maximum supply: 10 days — Minimum age: 3 years\". that 2 mg a day is the ceiling for supply without a prescription, not a prescriber ceiling: the forensic classification on the same page is \"PRESCRIPTION ONLY MEDICINES\", and the ndf page carries no posology section for this product, so no full label dosing schedule could be quoted. the cochrane review of children's asthma trials describes oral doses of \"not less than one mg daily\" given for 10 to 32 weeks. in singapore the prescriber or pharmacist sets the dose.","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["under 3 years — the sg supply exemption starts at 3 years","sedation is common — cochrane reported it in 21% of children treated","pregnancy or breastfeeding — nhs: pharmacist or gp advice first","older age, heart, liver or kidney disease or epilepsy — nhs advises asking first"],"clashes":[{"src":["nhs_anti_mix"],"food":true,"note":"nhs advises against it with any antihistamine, particularly a sedating one, as it raises the chance of sleepiness","with":"alcohol"},{"src":["nhs_anti_mix"],"note":"nhs lists these among medicines that could cause problems taken with antihistamines","with":"antidepressants, indigestion or ulcer medicines"},{"src":["nhs_anti_mix"],"note":"nhs flags doubling up on antihistamine through an all-in-one remedy","with":"cough and cold remedies containing an antihistamine"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/datasets/d_767279312753558cbf19d48344577084/view","label":"HSA — Listing of Registered Therapeutic Products (data.gov.sg dataset d_767279312753558cbf19d48344577084), Forensicclassification column; all 5,511 rows cached at /tmp/hsa_all.json and filtered locally (never re-fetched), 3 ketotifen rows, 27 Aug 2026","quote":"TOFEN TABLET 1 mg (SIN09651P), KETOTIFEN SYRUP 1 mg/5 ml (SIN08766P) and ASUMALIFE SYRUP 1 mg/5 ml (SIN10107P) all read \"Prescription Only\", ATC R06AX17; no Zaditen-branded ketotifen and no ketotifen eye drop is registered","accessed":"2026-08-27"},{"id":"ndf_tofen_class","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin09651p/","label":"MOH National Drug Formulary — TOFEN TABLET 1 MG [SIN09651P], Product information block","quote":"Forensic Classification: PRESCRIPTION ONLY MEDICINES · Anatomical Therapeutic Chemical (ATC) code R06AX17 · Active Ingredient and Strength: KETOTIFEN FUMARATE EQV KETOTIFEN - 1 MG","accessed":"2026-08-27"},{"id":"ndf_tofen_exempt","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin09651p/","label":"MOH National Drug Formulary — TOFEN TABLET 1 MG [SIN09651P], Prescription-only Medicines with Exemptions for Supply without Prescription","quote":"As an oral solid preparation not exceeding 2mg. Indications: Symptomatic treatment of allergic rhinitis and chronic urticaria. Maximum daily dose: 2mg. Maximum supply: 10 days. Minimum age: 3 years","accessed":"2026-08-27"},{"id":"cochrane_keto","url":"https://europepmc.org/article/PMC/PMC8406918","label":"Cochrane Database of Systematic Reviews — Ketotifen alone or as additional medication for long-term control of asthma and wheeze in children (Schwarzer, Bassler, Mitra, Ducharme, Forster, 2004; 26 trials, 1,826 children)","quote":"ketotifen alone or in combination with other co-interventions improves control of asthma and wheezing in children with mild and moderate asthma … Reported side effects were more frequent in the ketotifen group (sedation: 21%, weight gain: 27%)","accessed":"2026-08-27"},{"id":"tashiro2006","url":"https://europepmc.org/article/PMC/PMC1884984","label":"Brain histamine H1 receptor occupancy of orally administered antihistamines measured by PET: a comparison of olopatadine and ketotifen (Tashiro et al., Br J Clin Pharmacol 2006)","quote":"H(1)R occupancy after olopatadine treatment was significantly lower than that after ketotifen treatment in the all cortical regions … 5 mg oral olopatadine, with its low H(1)R occupancy and thus minimal sedation","accessed":"2026-08-27"},{"id":"nhs_anti_types","url":"https://www.nhs.uk/conditions/antihistamines/","label":"NHS — Antihistamines (conditions A–Z), types and how they work","quote":"Antihistamines block the effects of a substance called histamine in your body … antihistamines that make you feel sleepy … non-drowsy antihistamines that are less likely to make you feel sleepy","accessed":"2026-08-27"},{"id":"nhs_anti_who","url":"https://www.nhs.uk/conditions/antihistamines/","label":"NHS — Antihistamines: who can take antihistamines","quote":"speak to a pharmacist or GP for advice if you: are pregnant or breastfeeding … are an older person … have an underlying health condition, such as heart disease, liver disease, kidney disease or epilepsy","accessed":"2026-08-27"},{"id":"nhs_anti_mix","url":"https://www.nhs.uk/conditions/antihistamines/","label":"NHS — Antihistamines: taking antihistamines with other medicines, food or alcohol","quote":"Examples of medicines that could cause problems if taken with antihistamines include some types of: antidepressants; stomach ulcer or indigestion medicines; cough and cold remedies that also contain an antihistamine … Try not to drink alcohol","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:23.779398+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}